MD83 Rt Hyd Aux pump
 

Anyone seen this. Pump cavitation on morning start. Pump and reservoir have been replaced. You can work the hand pump and get it to stop and then pressure goes right on up to 3ooo. Or if you motor the Rt engine hyd pump, the aux pump will stop cavitating and work normal after the engine motoring stops. OK, the rest of the day - no other problems. Aux pump sw on, got pressure. Let the acft sit overnight,
same thing happens on wake up. This whole gitch just didn't happen, it slowly kept getting worse and worse. :ugh:

Long time ago since I had any MD time, and I know you have changed it but leaking diaphragm in the reservior is running round in my head. pinhole leak sort of thing.

I'll have to hunt out my old DC9 LAM book, not sure if I still have it.
Cavitation is lack of head pressure, so I would be looking at an accumulator. Since its only happening after a period of rest(overnite) then its a very small pressure leak.
Dont stop at the accumulators either, look for component leakage.

I have a MD83 Lamm in the garage, will look tomorrow. I agree it's a minute leak.

Well you only have two accumulators on the right system, brakes and rudder. Should be easy enough to isolate, then its components. What is the brake pressure like after an overnight stop.

Well Thursday we did a complete bleed and service per AMM 12-13. Will see Monday on wake up if it does it again...:rolleyes:

So which component did you replace?

irritating, ask a question, get replies, maybe fix, no feedback. Tosspot.

Nothing. A lot of hyd fluid later, bleeding air out of the system. So far it's been good. Our charters are not that frequent. The acft can sit days with no power on it, pump never tried. That when this problem would occur, after the long sit.